Oven burner ignition and control mechanism



Aug. 19, 1952 c. M. MAYER 2,607,416

OVEN BURNER IGNITION AND CONTROL MECHANISM Filed March 14, 1951 4Sheets-Sheet 1 l l L INVENTOR.

(Was. M Mayer BY ATTORNEY.

Aug. 19, 1952 c. M. MAYER 2,607,416

OVEN BURNER IGNITION AND CONTROL MECHANISM Filed March 14, 1951 4Sheets-Sheet 2 INVENTOR.

Jj4 INC/90.9. f7. Mayer flA fifMv Aug. 19, 1952 Filed March 14, 1951 c.M. MAYER 2,607,416

OVEN BURNER IGNITION AND CONTROL MECHANISM 4 Sheets-Sheet 5 ZINE ATTORNE Y.

' Filed March 14, 1951 4 Sheets-Sheet 4 19, 1952 c. M. MAYE'R 2,607,416

OVEN BURNER IGNITION AND CONTROL MECHANISM IN V EN TOR.

I %4/%JM A TTOR NE Y.

Patented Aug. 19, 1952 ovEN BURNER IGNITION AND CONTROL MECHANISM ICharles M. Mayer, Mansfield, Ohio, assignor to The Tappan Stove Company,Mansfield, Ohio,

a corporation of Ohio Application March 14, 1951, Serial No'. 215,481(Cl. 161-9) This invention relates to an'automaticignition and controlmechanism for ignitingand controllingathe operation of cooking rangeovens, and is a modification of the mechanism disclosed in the copendingapplications of myself and John M. Hoii', Serial No. 153,664, now PatentNo. 2,577,787, and Serial'No. 163,764, now Patent, No. 2,578,717, filedApril 3,1950, and, May 23, 1950, respectively. It is designed for usewith a clock actuated time control mechanism, which automaticallyeffects the turning on and off of the oven burner at predetermined settimes, but is also arranged to be usedindependently of the time controlmechanism in which case the oven burner is manually turned on and oii asdesired;

The mechanism is designed for use with a main gaseous fuel burner andincludes a gaseous fuel pilot burner by which the main burner isignited. The mechanism is soconstructed and arranged that the mainburner is under the control of the pilot burner at all times The, pilotburner must be ignited in order for gas to be supplied to the mainburner. Should the pilot burner be extinguished iorany reason duringoperation the supply of gas to the main burnerwill be promptly cut off,and it cannot again be supplied until the pilot burner has beenre-ignited. This arrangemerit-provides asafetyfeature which prevents.

the accumulation of unburn'ed gas in an oven which;may violentlyexplodewhen an attempt is mad .to're ignite "either the main or pilot burner.It has been foundby experience that both the main burner and the pilotburner in cooking range ovens are frequently extinguished during useior'some'reason or other without being turned off.' This is sometimesdue to a momentary gas failure or to the slammingof the oven door or tovarious other ca'uss.' I

The mechanism includes in addition to'the pilot burner a manuallyoperable main control valve, a safety control valve mechanism, athermostatically operated oven temperature control valve, a'sclenoid bywhich the safety control valve mechanism is initially set in conditiontosupply gasto the pilot burner, an electric-ignition element by whichthe. pilot burner is ignited, a pair of normally openv manually operableswitches, a normally 'closed switch which isfadapted to be opened .by athermostatic element mounted in position .to be heated by the pilotburner, a clock operated switch [and electric circuits which ineludevthe aforesaid switches, the electric ignition element and the solenoid.I

The main control valve isa standard cut-elf valvehavinggonelclosed oroff position and two;

25' Claims;

open or, on positions. When this valve is turned to one on position themechanism is set for man ual control of the cooking time, and When it isturned to the other on position the cooking time is automaticallycontrolled by the time control mechanism. In operation gas flows fromthe supply manifold, through the main control valve and into the safetycontrol mechanism. From the safety control mechanism the gas flowsthrough one conduit to the pilot burner and through another conduit tothe oven temperature control valve and from there to the main burner.

The safety control mechanism comprises a casing having a gas inlet port,a pair of gas outlet ports, one to the pilot burner and one to the mainburner, a pair of valves and an electromagnet which is energized by athermocouple which is mounted in position to be heated by the pilotburner. One of the valves is normally closed and is operative in closedposition to cut off the flow. of gas to, both the pilot burner andthemain burner; and the other valve is normally open and is operativewhen in closed position to cut off the flow of gas-to the mainburner'while permitting gas to flow to the pilot burner. The solenoid isoperative when energized to close' 'simultaneously the normally openvalveand to open the normally closed valve; fand'the electromagnet isoperative whenenergized' to maintain the normally closed valve openafter the solenoid has been de-ener gizedl I The two normally openswitches are operatively associated with the main .controlvalve and arearranged to be closed by the opening of the main' control valve and tobe opened by the closing of the valve. One of the switches is actuatedwhen the control valve is turned'to and from one of its open positionsand the other switch is actuated when the control valve is turned to andfrom the other of its open positions.

To initiate operation of the main burner under manual .controlfof thecooking time,'the main control valve is turned-to the proper openrposiation which closes the associated normally open switch, The closing ofthis switch effects the. energiz'ation of the electric ignition elementand the solenoid. The solenoid then simultaneously closes the normallyopen valve in the safety control mechanism'and opens the normally closedvalve. Gas can then flow to the pilot burner but it cannot flow tothemain burner; The pilot burner is then ignited bythe electric ignitionelement and projects aflame against and heats both the thermocouple landthe thermostatic element. The heating ofthe thermocouple gencrates aminute'cu'r'rent of the order of 1009110 semis and the electromagnetwill hold the normally closed valve open. Gas can then flow to the mainburner where it is ignited by the pilot burner. The main burner willthen operate under control of the oven temperature control valve as longas the main control valve is open andthepilot burn or is ignited andheating the thermocouple and thermostatic element. If the pilot burneris'extinguishecl for any reason during operation the thermocouple andthe thermostatic element will immediately cool. The cooling of thethermocouple will de-energize the electromagnet which will releasethenormally closed valve whichwill then return to its closed positionand cut off the flow of gas to both the pilot burner and the mainburner. The cooling of the thermostatic element will close the normallyclosed switch which will then effect re-ener'gization of the solenoidand the electric ignitionelement. The solenoid will then open thenormally closed valve and close the normally open valve, thus supplyinggas to the pilot burner only. If the pilot burner is then re-ignited itwill re-heat the thermostatic ele-' ment andthe thermocouple,thusre-initiating operation after which the mechanism will operate asdescribed. To terminate operation the main control valve is manuallyclosed.

In addition to the aforesaid possibilities of accumulating unburned gasin an oven, there is one other condition under which unburned gas couldcollect "in an oven'. My improved control apparatus is also designed totake care of this contingency and prevent the-accumulation 10f unburnedgas in an oven should this condition ever occur. For exaniplaassume thatwhile the main burner is operating normally the main control valveisclosed and'then immediately opened again before the thermocouple. andthe thermostatic element'have had time tocool; The closingof the maincontrol valve extinguishes'both the main burner and the pilot'burner bycutting 01f the supply'of gas thereto. Then when the-main control valveis immediately reopened gas is again supplied to both themain burner andthe pilot burner, since the thermocouple has not'had time to coolsufficiently to allow the safety" control valve mechanism to operate tocut off the supply of gas to both burners. But under this. condition thepilot burnery'v iil not be ignited because the still hot thermostaticelement is maintaining the'normally closed switch open and preventingenergization'of the electric ignition element and of the solenoid.Thus'unburned gas "will escape fromfboth the main burner and the pilot'burner' into the oven until the th'ermostaticelement cools and closesthe normally closedswitch; As soon as the thermostatic'element coolssufficiently it will" eriergize the ignition element which will ig'e'nitethe pilot burner and it in turn-'will ignite; bthe main burner. But"inthe meantime-enough" gas may have' escaped -into the"oven"from themain burner and the pilot burnerto cause a bad explosion when the pilotburneris again'ignited; In' order to eliminate the escape of anyunburned" 4 gas into the oven whenever this condition o curs, I providean interrupter switch in the circuit between the thermocouple and thesafety control valve mechanism. This switch is arranged to be opened andclosed by the closing and opening of the main control valvesimultaneously with'the opening and closing of the master controlswitch. Then when the main control valve is closed to out off the supplyof gas to the burner, the interrupter switch is simultaneously opened,breaking the circuit between the thermocouple and the safety controlmechanism which permits the safety control switch mechanism to cut ofiall communication to both the pilot burner and the main burner. Thenwhen the main control valve is immediately opened after havingbeenmomentarily closed, nothing will happen until the thermostatic elementscools and closes the normally closed switch which occurs between six andten seconds. After that the apparatus functions in its normal manner, ashas been explained.

For automatic operation I provide a clock actuated time controlmechanism which may be set a to initiate operation of the main burner atapredetermined'set time and to terminate operation thereof at apredetermined set later time.

switch which is in series with one of the normally open switchesassociated with the main control valve. For automatic operation the timecontrol is set to initiate operation at the desired time and toterminate operation at the desired later time and then the main controlvalve is turned to the proper open or on position which closes thenormally open switch associated therewith. At the set time the timecontrol mechanism will automatically close its normally open switchwhich will effect energization ofthe solenoid and the electric ignitionelement after which the mechanism will function'exactly the same as withmanual control until time to terminate operation, at which time the timecontrol mechanism will automatically open the associated normally openswitch which will, as is hereinafter described,

effect the breaking of" the circuit between the thermocouple and theelectromagnet. The electromagnet then releases the normally closedswitch of the safety control mechanism whichreturns to its closedposition'and cuts off the flow of gas to both'the pilotburner and themain burner, thus terminating operation.

The various component parts of the mechanism are so constructed andarranged that gas cannot be supplied to either the main burner or thepilot burner in the event the electric ignition element has been brokenor burned out.

Means are also provided by which the oven burner can be manually ignitedand controlled in the event of a power failure.

The principal object of the invention is to pro-' VIdG an improvedelectrical ignition and automatic control system for cooking range ovenburners using gaseous fuel.

Another object of the invention is to provide in an electricignition'and control system of the character described improved meansfor completely shutting off the supply of gas toboth the main burner andthe pilot burner in the event the pilot burner is extinguished for anyreason beforethe supply of gas to both the main burner anld the pilotburner is cut off by the main control va ve.

Another object of'the invention is to provide in an apparatus of thecharacter described The time control mechanism includes a normally openimproved means for automatically cutting'ofi the Supply of gas to boththe main burner-and; the pilot burner in the event the electric ignitionelement hasbeen rendered inoperative to ignite the pilot burner.- YStill another object of the invention is to pro vide in'an apparatus ofthe character described; improved means to prevent. theescapeof any.unburned gas in the event the main control valve is turned off after aperiod ofoperation and then is immediately turned back on beforevtheheat responsive elements-in the system have had time tocool. g Otherand more limited objects of the invention will be apparent from thefollowingspecification and the accompanying drawings formingapartthereof, wherein Fig. 1 is a diagrammatic layout illustrating myImproved automatic ignition and control mecha} nism applied to a cookingrange oven burner using gaseous fuel; I

Fig. 2 is an'enlarged central longitudinalvertical section through thesafety control mechanism showing the various parts in the positions theyassume when the oven burner is turnedofij; Fig. 3 is aviewsimilarto Fig.2 showing the various parts in the positions they are-automaticallymoved to when the main control valve is first turned on to initiate theoperation of the main oven burner; I 1

Fig. 4 is a horizontal section, taken on the line .4 F ;j Fig. 5- is awiring diagram of the mechanism, and

two open or onpositions. {In either ofltheopen positions it permits theflow .ofv gas .from the manifoldM to the burner I, and in the closedposition itcompletely cuts off the flow of gas fromthe manifold M. Inone open position of the main-control valve 4 the mechanism is set formanual control and in the other open position the [mechanism is set forautomatic control. This valve is manually opened and closed by a handleI and a valve stem 28, and directly controls the operation of the entireapparatus in that it initiates the operation .of the entire apparatuswhen it is turned to either of the on positions, and terminates theoperation when it is turned to the on position. From the main controlvalve Fig. 6- is a view similar-to Fig. 5 showinga 6 perature;settingby, a thermostatic, element ,I4 which is-mounted in the oven'2and is connected to'the valve fi, as shown at I5. The oven temperatureeontrol valve 6 is; of standard, .well

known construction. Consequently it is not shown-in detail herein.-There are manydifi'erentponstructions available, any one of which willwork equally well herein. Gas is also supplied to-a pilot burner -I 6through a branch conduit I'I which'extends-between the safety controlmechanismand thepilot burner I6. The pilotburner |6 '-IIS disposedadjacent ,one end of the main burner. .Linposition to ignite the burnerI when gas is vsuppliedthereto. An electrical ignition element I8 isoperatively associated with the pilot burner I6;in position to ignitethe pilot burner lfi when gasis supplied thereto. A thermostatic element19 and a thermocouple 20 are mounted in position to be heated-by a flamefrom thepilot burner j The thermostatic element I9. is operative to open.andclose a switch 2I which controls the energizationof the electricalignition element I 8 and; a solenoid 22 which when energized oper-. atesthe safety control mechanism to supply gas to-the pilot burner 16, aswill be described in conneetionwith the descrip ionof thesafety controlmocha 's'mand the operation of the whole apparatus, {The thermocouple 20when heated is operative to holdthe safety control-mechanism incenditiontomaintain the supply of gas to both thepilot burner I6 and the mainburner I, as will. also be; described in connection with thedescriptionof the safety control, mechanism and the operation ofthegapparatus. r

A pair, oftnormally open master switches 23; and Z4. areoperativelyassociated with the valve stem- 8 of the main control valve. 4 and areadapted-tobe closedand opened by-the opening. and closing of the valve 4As the valve stemt. is turned ina clockwise direction to setthe valveinoneopen position-th switch 23 isclosed by a cam-3'5; onythe valve stem8 through a link 26;. and when the valve stem 8 is rotated in acounterclockwise direction to set the valve 4 in itsother. open-position,- the switch 24 is closed by the cam g ,through the link 26.Conversely when they 4 gas flows through a connector 9 to thesafetyvalve 6 is set. to any desired temperature by a.

handle IIxhaving a pointer I2 which-cooperates with a graduated dial I3vcarried by the .Valve 6.;

The: valve 6 is controlled according to the .tem'-'.

valveg4-isgturnedfrom either open position to the closed.positiontheclosed switch 23 or 24 will be opened. I The construction ofthe' safety control valve.

mechanism fa and its connection to the solenoid 2Z wi1lnowbedescribed'reference being had to Figs. 2-, 3 and 4 of thedrawing.This mechanism comprises acasing 35 having a chamber 36 in one endthereof and a. chamber 31 in the other end thereof. The chambers 36 and31 are connected bya :bore 38 of reduced diameter. A valve seat. 39 is'located at one end of the bore .38 and a similarvalve seat 40 is locatedat the other end of. the bore 38. The chamber 3K5v is closed byaremoyable cap: 4| and the chamber 31 is closed by aremovable cap 42. Asleeve 43, having end walls 44; and 45, is carried by the cap M and thechamber 36 into the sleeve 43. A valve disc 48' of suitable material issecured to one end of the valve stem 46 within the chamber 36, and ametal disc 49 is secured to the other end of the stem 46 within thesleeve 43; A spring 50 disposed about the valve stem' 46 between thevalve disc .48 and'the endwall 45 of the sleeve 43 normally holds thevalve 'disc 48 against the valve seat 39. An electromagnet 5| is securedto one end "of a hollow exteriorly threaded stud 52 'which' exteneeoutthrohgh-ali'gned apertures in the end wall ioi the sleeve 43;- and inthe end of the cap-"41 i 53'scr'ewed onto the outer portion er -fin s udaz secureiy holds'tlre-mag'net 5| and the le ac es "place.The-legs-of"the electromags t l-l1 have a windin-g'fiithereon, one'endof war is connectedto-a copper tube 28 which extends bet'ween the therhiocouple-zfl and the safty c ntroi-c; and t-he other end of which isconnected to an insulated wire 29 within the tribe- 28-Lfl The'tube 28and'the-wire 29 therein establish anelectric circuit between thethermocouple ZU- and' thewinding fl of theelectrornagnet '51. T bewts-insertedinto the hollow stud-'52 held ihplacewby a screw fitting 30'.A 55 3s screwed into a-threaded recess in-the f the cap El as-indicatedat 56; and extends V ech'amb'erfi-l a slight distance. One-end slee've55as closed b'yan end wall 51-, and ther -end which is open registers witha circdl'a perm-re- 58in theenc wallof the-cap '42. A' plu e isslid-ahly-mou nted in the sleeve 55 and extends one: through theaperture 58 in the cap to enga e thevailve seat 420 cut oh" the-flow ofgaszintoithe chamber 3 during the-initiation of operation, as will behereinafter described. A compressionispring 66; disposed about'the stemGZZbEtWeen the'en'd'wall EI and-"the valve disc 65,

normally yielding-1y holds the valve disc 65' aigainstith'ecollar-'64Aco'mpres'sionspring 61 whichis stronger than the spring 66 is-disposedabout: the stein z within the-sleeve between the" innerface; oi the endwa'll 51 and "the inner endiof'th'ei-pliig S9: The spring, fi'li'sopei'ative to return the plug 59, stem 62 and valve disc 6'5 from theposition shown in I Fig.- 3 backto their normal positionlas shown-inFig. againstthe" resistance: of :thespring- 6 6. A-port 68 in the casing Sea-provides communication between the chamher. Sfi' and f theconnector 9 to allow gas to flow from th'e main control-valve4 throughthe connector: 9"and into thecnamberat. During riermal fop'eration.of-the' main burner I gas-flows froniithe. vchamber 36 throu-g h thereduced inter' mediate bhiefi38 ahd'iritb the chamber 37. 69 whichestablishes communication between the conduit .1 l Landithe bore 3'8 isprovided to-supply gasstothepilotburner l6; and a port'lflestablisheszcommunication between the chamber- 31 andith'eiconnector I 8 toiperm itthe 1 flower gasfromthe chamber 31' to: the:mainburner I through :tl'reioven temperature-"control valve 6 andthefrconduit 3.. g l

flhesafety; control;valvewinechanisrnlii is operatively connected to.therrsolenoid 1 22irbyta yoke I2-'anda:linlc.7-3.: 'The yol :e:- 121which enco'm passes ther'saiety contro'lrvalvezmechahism 5;.a's

shown-in Fig-r4; comprises: aapairrof" s'pacedipare'allel-rrarinsultwhichiare connected together at oneend-lbyy'abridgefliThei bridge' l5-fhas an aper= ture 76 therein thrOughwhich the reducedend A port- 8 fifl' of-the-pliig 59 extencswith the'inner face of thebridgeengagingtheshoulder 6| between the plug 59- ahd the-reduced'extension 68' thereof; The'bther'endsof the arms terminate in a pair ofspaced parallel ears I! to and between which =ohe-end ctthe link 13'; is'pivo'tally' connected. The other end ofth'e link 13 is pivotallyconnected to themov able core '18 of the solenoid 2 2}asindicated at 19:

a In crderto-eliminate'theescape of unburned asinthe evemthemain controlvalve 4 1s turned ofB'aftei' a periodof operation and is immediatelyturned back on, I provide an interriipter switch 80 m the circuitbetween the thermocohple 2'0 and the electromagnet 8!.- The Switch 8'0-is as'tandard mercury switch which is arranged to be moved from open toclosed position by a sole'noid transformer -8 l through a link- 82;and-to Ice-moved from closed to open position by a s'pring83; connectedto the link 82, which normally holds the switch 88 in open position. Astop 84-i's provided to-liniit the opening movement of the-switch 80. I

Thesolenoid-transformer 8! comprises a stationary core 85;"a'mo'v'ab1ecore 86, a primary winding 8-! 1 and a secondary winding 88.

fin orde'r to accommodate the mechanism for automatic-control, I providea clock operated time control mechanism of standard construction whichcomprises a clock"!!! and a "nor mallyopenswitch 9 2- which isadapted tobe automatically closed and opened at-predeter-' mined-times accordingto the setting of the clock 9|, which may be set as desired by thebuttons 94 and 95; The switchB-Z is disposed in series with the switch24and is operative when closed to"ini-tiate and-maintain operation ofthe main binnerl. Th?operation of the-apparatus independent 1y;of-"thetime control mechanism willnow be described-in connection withFig; 5. Toinitiate theoperationof the oven burner' I it is'only ncessary 'to setthe oven temperature control valve-6-to the de'siredte'mperature and toturn manuallythe maineontrol valve 4 clockwise f ro'm'th'e off'positionto one on-positionl After that theignitionand-operation. of the burnerare-=a1ftomatically "controlleduntil the I operation ofthe -hurnr isterminated by manually turning'the inain controlvalve 4 from, theon-position tojthe-off position. 'Asthe main control valvelisturnedfi'om thenff position to the onposition the: master switch '23is closed by the cam 25 link '28; After'themain control valve hasbeen-:opened-gas can'fiow from the manifold thr'oughthe inaincontrolvalve 4 and into the chamber of the safety control valve me'ch--aniisintj thevari-ous parts'of which are inthe position shown in Fig; 2.But the gas can go no'fa rthersincethe valve disc 48 is being heldagainst the vaive'seat '39 'by the springfiil thus closing the 'only'exit -fromthe chamber 36. As soon'as the switch 23; is-closed'currentflows from therpositive; side we of the line through the leadfl flli'totheiswitch'fl; From the-switch 23 the'cnrrentflows-"through thelead I02 to one side-"of the primary winding 87, ofthe'solenoidtransformenfil, and 'from theother side of theprimaryWin'ding- BJ back to the otherside I03 'e-"lihe---throii'ghthelead N14; The electric tanc'e ignition element 18,.the normallynectedzin'iseries .with the secondary winding 88 of thl'enoid tra'nsformer 81- by the leads I05; H16; 10 1? and 108'. ."Thefclosing of lthe switchx23 solenoid 22.

bore 38 and the chamber 31.

9 thus energizes the solenoid-transformer .8 .I which throughthe-movable core 86 thereof. and the link 82 c1oses the mercury switch.80 and makes the circuit between the thermocouple 20 and theelectromagnet 5|. The solenoid-transformer 8| when energized alsothrough the secondary winding and circuit I05 to I09 energizes theelectric resistance ignition element l8 and the The secondary currentgenerated by the solenoid transformer 8| is'of much lower voltage thanthe line current. The electric ignition element I8 and the solenoid. 22are now both energized. The energizing of the ignition element l8renders it operable to ignite the pilot burner l6 as soon as gas issupplied thereto, and

the energization of the solenoid 22 causes it,

through the link 13 and'yoke 12, to shift the various parts of thesafetycontrol mechanism from the f position shown in Fig. 2 to the positionshown in Fig. 3. In'this position the valve disc 48 is held away fromthe-valve seat 39 and the metal disc 49 is held against the ends ofthe-legs of the magnet 51 by the stem 62 acting against the resistanceof the spring 50. This allows gas to flow from the chamber 36 into thebore 3 8 and thence through the port 69 and conduit ll'to the pilotburner [6 where it is ignited by the ignition element I8. flow to themain burner l since thevalve disc 65 is being held against the seat 40by the spring 66 which cuts oif communication between the As soon as thepilot burner I6 is ignited it projects. a flame against and heats boththe thermocouple 2D and the thermostatic element l9. The heating of thethermocouple generates a minute current of the order of .009to .017 voltwhich energizes the eleotromagnet-5l sufficiently for itto hold themetal disc 49 and the stem 46 and valve 'disc 48 secured thereto in theposition shown in Fig.

3 against the pressure of the spring 50 after the disc 49 has beenmoved'into engagement with the magnet 5| by the solenoid 22. But the manet 5| when energized by the thermocouple 20; 'is not strong enough toattract and withdraw the metal disc 49, and the stem 46 and valve disc48 secured thereto, from the position shown in Fig. 2 to the positionshown in Fig. 3. It can only hold these parts in this position afterthey have been moved thereto by the. solenoid 22 through the medium ofthe link 13, yoke 12, plunger 59 and stem 62. The electric circuitbetween the thermocouple 20 and the winding 54 of the magnet 51 isthrough the copper tube 28 and the wire 29. This circuit will bemaintained as long as the thermocouple is heated. After the thermostaticelement l9 has been heated sufficiently, which is after the thermocouplehas energized the magnet 5|, it will open the normally closed switch 2i,breaking the circuit to and de-energizing both the ignition element l8and the solenoid 22. After the pilot burner has been ignited there is nofurther need to maintain the ignition element energized. As soon as thesolenoid 22 is de-energized the spring 61 will return the plunger 59,stem.62 and valve disc 65 back from the position shown in Fig. 3 to theposition shown in Fig. 2 .against the pressure of the spring 66. Thevalve disc 48 will be held in the position shown in Fig. 3 by the magnet5|. Communication isthen established between the chamber 36 and 31through the bore 38. Gas will then flow from the chamber into'thechamber 31 through the bore 38. From the chamber 31 gas will flowthrough the oven But the gascannot yet 10 H temperature control valve' 6and conduit 3 to the main burner I'where it will be ignited by the pilotburnerlfi; The apparatus is now op- .eratingnormally, and in the absenceof any abnormal condition it willcontinue to do so, provided the lpilotburner remains ignitedhuntil the supply ofgasto both the pilot burnerand themain burner is cut off by the manual closing 'of the main controlvalve 4.

In theeventthe pilot burner I5 is extinguished for 'anyreason' duringoperation, the thermocouple 2i!v will cool .in a few seconds andde-energ'ize the magnet 5|. The de-energizing of the magnet 5|. willallow the spring 50 to'move the .y'al've disc. .48 backinto engagementwith-the valve seat. 39, as shown in Fig.2, which will -cut 01f the flowof gas from the chamber ilii into the bore 38 and chamber31, and fromthemto the pilot light I6 and the main burner I. The burner I will thenbe extinguished, along with the pilot burner. .As soon as thethermostatic element [9 cools it will close the switch 2| which willenergize both the ignition element l8 and the .solenoid 22, aspreviously described, provided the ignition element It is intact, sincethe main control valve 4 is still open and'the switch 23.is.closed. Thepilot burner [6 will then be re-ignited and the rest of the apparatuswill again function as described, provided there is gas available. linegas is available everything will remain in condition to ignite the pilotburn er and re-initiate operation as soon astgas is again available. 3 gL If, however, the ignition element [8 has been broken or burned out orotherwise affected so that current cannot pass therethrough, thesolenoid 22 cannot be re-energized since it 'is'in series with .theignition element l8. Consequently the valve 48 .will remain closed, asshown in Fig. 2, cutting off the supply of gas to both the main burnerand the pilot burner. In the. event of either a momentary or prolongedpower failure duringoperation, the apparatus will continue to operatenormally until terminatednb'y the manual gclosing of the main controlvalve, provided of; course that all other conditions are normal. Inorder to operate the apparatus during a prolonged power failure whichoccurred prior to operation, I extend the link 82 so that it can beengaged and shifted by the cam 25 to move the switch 80 from open toclosed position,- as the main control-valve lis opened by a clockwisemovement of the valve stem 8. Thus in the event power is not available,the main burner i can be operated by opening'the main control valve 4 ina clockwisedirection and then holding a match to the pilot burner l6 andmanually moving the'plunger 59' from the .posi'--' tion shown in Fig. 2to the position shownin Fig. 3 and holding it in this position asufficient time for. the thermocouple 20-to become-heated, after whichthe plunger 59 may bereleased and allowed to be returned to its initialposition by the spring 61. tinue to. function normally as described,under the control of the pilot burner l6 and the oven temperaturecontrolvalve 6. 7

When the apparatus is used in conjunction with the time controlmechanism 90, the time controlmechanism is set to initiate operation ofthe main burner I at a predetermined time'and to terminate operationthereof at a predetermined later time. After the time control mechanismhas been set, the main control valve 4 is manually opened in acounterclockwise direction which The apparatus will then con- 7 l1closes the master switch24. Then atthe, predetermined set'time the" timecontrol mechanism willclos'e the switch 92. pC'urrent'will thenv flowfrom the positive side Ifililof the line throughjthe lead I09 to theswitch 24. From'the switch '24 the current will fiow'through the leadIII] to the switch 92 and from the switch'92 to the primary 7 winding-81 of the solenoid-transformer 8| through the leads III and I92. Fromthwi'nding 8! the current will fiowb'ack to the negative side I 03 'ofthe line through the lead I04, thus completing the circuit to andenergizing the solenoid-transformer. The solenoid-transformer willthenclose the switch'tfl and energize" the ignition element I 8 andsolenoid22 whiclrwill initiate operation, as previously described. "Themain burner I will then operate underthe cona trol of the pilot burnerI6 and oven temperature control valve 6, as previously described, untilits operation is terminated bythe opening 'ofthe switch 92 by the clock9|. The opening of the switch 92 will break the circuit tothesolenoidtransformer 35 whichi'will allow the spring"83 to shiftthe-interrupter switch 80 to :operrpo'sition. The'opening of the switch80 will break the circuit to and de-en'ergize'the electromagnet-EI whichwill then release the valve 48, which, when released, will return toclosed position and'cut oifthe supply of gas to both the main burner andthe pilot burner, thus'terminating operation.

The main control can then be manually closed anytime later.

In Fig. 6 I have shown a slightly modified form of the invention. Inthis form of the invention 7 I connect the solenoid 22 directly to theline i INI-v I03 by the leads Hi and II 6, a'nd I interpose a;relay'I'I'l in' the'secondary circuit I05 to 108 in place of thesolenoid 22. In'the lead H6 between the line IOU-I03 and 'thesolenoid22' I interpose a-normally open switch I I8-which is biased tolopenposition-by a spring I IS). The relay I I7 isdisposed in operativerelation to the switch H8 andis operative when 'e'nergized to maintainthe switch I I8-in closed positiomOther wisefthe construction andoperation of this formof the invention is identical with theform" shownin Figs. 1 to 5 and the same reference characters are applied tolike-parts.

a In the form of the invention when the switch 23 .or-the switches 24and 92 are closed the solenoid-transformer BI will close the switch- '80and effect the energization of the electric igni tion element I8 and therelay II I. The relay III will then close the switch I I8, therebyenergiz'ing the solenoid "22 which will actuate the in the secondarycircuit which will de-energize the electric ignition element I8 and therelay I II. The spring H9 will then open the switch 8' and de-energizethe solenoid 22 after which,

the apparatus will operate as previously. described in connection withFigsel to 5.

From the foregoing it will be seenthat in the event, the pilotburner:isextinguishedfor any reasonthe supply of gas to both themain'burner andv the pilot burner will becompletely, cutoff, thus.eliminating all possibilityof anexplosion due to an accumulation ofunburned gas; and it will ,be apparent tothose skilled." in. thisartthat I haveprovided a very simple and efficient apparatus foraccomplishing the objects offthe. invention. I a I;

It isto beunderstood that I am not limited to the specific constructionshown and'described herein as various modifications may be made therein"within the scope of the appended claims,

What is'claimed is:

1,.In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner,"'a pilot burner operativeto ignite said main burner, an electric. ignition "element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied'to said mainburner, a manually operable maincon; trol valve bywhichthe. supply of fuel; to said main burner is primarily controlled, asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel is sup-. plied to said pilot burner, saidsafety control valve mechanism being operative to control, the supply offuel to said main'burner-after'said' main control valve has beenopenedQasolenoid by which said safety control valve mechanism is set incondition to supply fuel to said pilot burner and said'main burner, anelectromagnet associated with said safety control valve-mechanism andoperative when energized to maintain said safety control'valve mechanismin said set con dition, a thermocouple adapted to be heatedby said pilotburner, an electric circuit betweensaid thermocouple and saideleetromagnet through which said electromaghet is energized by saidthermocouple when heated, a normally open switch in said'thermocouplecircuit, a solenoidtransformer having aprimary winding and a secondarywinding, a master switch operative when closed to effect energization ofsaidsolenoid-transformer, a primary circuit which includessaidprimary'windingand said master switch, a secondary circuit in whichsaid electric ignition element-said solenoid and said secondary windingare disposed in series with each other, said solenoid-transformer beingoperative when energized to close said normally open switch and toenergize saidelectric ignition element and said solenoid, and meansoperative to break said iii) -. (if) cause it to 'open' the normallyclosed switch 2I secondary circuit and dc-energize said electricignition element and said solenoid after said pilot burner has beenignited by said electric ignition element.

2. In an automatic ignition and control apparatus of the characterdescribed, the combina-' tion of a'main burner, a pilot burner operativeto ignite said main burner, an electric ignition element operative toignite said pilotburner, a conduit through which gaseous fuel issupplied to'said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner and said pilot'burner isprimarily controlled, a safety control valve mechanism interposed insaid conduit between said main control'valve and said main burner andoperative to control the supply of fuel to said main burner and said.pilot burner after the fuel leaves,

said maincontrol valve, a secondary conduit extending between saidsafetycontrol valve :and

- said pilot burner through-which gaseous-fuel is 13 supplied to saidpilot burner; said safety control valve mechanism including a normallyopen valve and :a normally closed valve, a solenoid operativelyconnected to said safety control valve mechanism,'said solenoid beingoperative upon energization .to close said normally open valve and;toopen said normally closed valve and upon subsequent de-energiza'tion toreopen said normall-y open valve,. an electromagnetassociated with saidsafety control valve mechanism and operative when energized to maintainsaid normally closed valve open after it has been opened by:.the1 actionof said solenoid whereby fuel is first supplied to said'pilot burneronly and then upon the subsequent de-energization of said solenoid fuelis supplied to both said pilot'burner and said main burner, athermocouple adapted to be heated by said pilot burner, an electriccircuit between said thermocouple and said electromagnetfthrough whichsaid electromagnet is energized by said thermocouple when heated, anormally open switch in said thermocouple circuit, asolenoid-transformer having a primary winding and a secondary winding, amaster switch'operative when closed to effect energizatio'ncof saidsolenoid-transformer, a primary circuitv whichrincludes said primarywinding and said master 'switch, a secondary circuit in which saidelectric ignition element said solenoid and said, secondary winding aredisposed in series with each Tother, said solenoid-transformer beingoperative when energized to close said normally open switch andv toenergize said electric ignition, element and saidsolenoid, and meansoperative to break said secondary circuit and deenergize said electricignition element and said solenoid after said pilot burner has beenignited by said electricignition element 3. In an automatic ignition andcontrol apparatusof the character described, the combinationrof amainburner, a pilot burner operative to ignite said main burner, anelectric ignition element operative to ignite said pilot-burner, aconduit through which gaseous fuel is supplied to.v said main burner,famanually operable main control valve by which the supply of 'fuel 'tosaid main burner is primarily controlled, a safety control valvemechanism interposed in said conduit between said main control valve andsaid main burner, a secondary conduit extending between said safetycontrol valve mechanism and said .pilot burner through which gaseousfuel'issupplied to said pilot burner, said safety control valvemechanism being operative to control the supply of fuel to said mainburner after said main control valvehas been opened, a solenoid by whichsaid safety control valve mechanism is set in condition to supply fuelto said pilot burner and said'main burner, an'electromagnet associated.with said safety control valve mechanism and operative when energized"to maintain said safety control valve mechanism in said'set condition, athermocouple adapted-to be heated by said pilot burner, an electriccircuit'between said thermocouple and said electromagnet through whichsaid *electromagnet is energized by said thermocouple when heated, anormally'open switch in said thermocouple circuit,,a cam associated withsaid main control valvev and operative to close said normally openswitch simultaneously with the opening of said main control valve, atransformer having a primary'winding and a secondary winding, a masterswitch operative when closed to effect energization of said transformer,a primary circuit which 14 includes said primary winding and said masterswitch, a secondary circuit in which said electric ignition element saidsolenoid and said secondary winding are disposed in series with eachother, said transformer being operative when energized to energize saidelectric ignition element and said solenoid, and means operative tobreak said secondary circuit and de-energize said electric ignitionelement and said solenoid after said pilot burner has been ignited bysaid electric' ignition element.

4. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said mainburner is primarily controlled, asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel is supplied to said pilot burner, said safetycontrol valve mechanism being operative to control the supply of fuel tosaid main burner after said main control valve has been opened, asolenoid by which said safety control valve mechanism is'set incondition to supply fuel to said pilot burner and said'main burner, anelectromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a thermocouple adaptedto be heated by said pilotburner, an electric circuit between said thermocouple and saidelectromagnet through which said electromagnet is energized by saidthermocouple when heated, a normally open switch in said thermocouplecircuit, a solenoid-transformer having a primary winding and a secondarywind-' ing,- a master switch inoperative when closed to effectenergization of said solenoid-transformer, a primary circuit whichincludes said primary winding and said master switch, a secondarycircuit in which said electric ignition element said solenoid and saidsecondary winding are'disposed in series with each other, saidsolenoid-transformer being operative when energized to close saidnormally open switch and to energize said electric ignition element andsaid solenoid, and means operative to break said secondary circuit andde-energize said electric ignition element and said solenoid after saidpilot burner has been ignited by said electric ignition element, saidmeans comprising a normally closed switch in saidsecondary circuit and athermostatic element adapted to be heated by said pilot burner andoperative when heated to open said normall closedswitch. Y

* 5;In an automatic ignition and control appa ratusiof the characterdescribed, the combination of a main. burner, 'a pilot burneroperativeto ignite'said main burner, an electric ignition elementoperative to ignite said pilot burner, a-conduit through which gaseousfuel is supplied to said main burner, a manually operable main controlvalve by which the supply of fuel to said main burner is primarilycontrolled, a safety control valve mechanism interposed in saidconduitqbe tween said main control valve and said main burner, asecondary conduit extending between said safety control valve mechanismand said pilot burner through which gaseous fuel supplied to: said pilotburner, said safetyfcontrol control valve has been opened, a solenoid bywhich saidsafety control valve mechanism is set incondition'tosupply'fuel toisaid pilot burner and-said main burner, an electromagnetassociated with said safety control 'valvemechanism andv operative whenenergized to maintain said safety controlvalve mechanism in said setcondition, a thermocouple adapted to be heated by said pilot burner, anelectric circuit between said thermocouple and said electromagnetthrough which .-said-;-electromagnet is energized. by said thermocouplewhen heated, a normally open switch in: said thermocouple circuit, acamassociated with said main control valve'and oper' ativeto-close saidnormally open switchqsimultaneously with theopening of. saidmain-control va-lvawa transformer-having aprimary winding 311C118,secondary winding, a master switch operativer when closed, to effectenergizationlof said transformer, a primary circuit whichincludes saidprimary-winding and said masterswitch, a secondarycireuit in which saidelectric ignition element said solenoid and said secondary wnding aredisposed series with each other; said trans former bei-ngoperative whenenergized to energize said; electric ignition element and saidsolenoid,v and .means operative to break said, secondary circuit, andde-energize said electric ignition element. and said solenoid after saidpilot burner has been ignited; by said electric ignition element, saidmeans comprising a normally, closed .switch in saidisecondary circuitand-a thermostatic element adapted to be heatedby said pilotburnerandoperative when heated to open saidnormally closedswitch.

.6. Inch automatic ignition and control apparatusof the characterdescribed, the combination of -a-main,burner, a pilot burner operativeto ignite said main burner, an electric-ignition elementope-rativetoignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner is primarily controlled, asafety control-valve mechanism interposed in said conduit between'saidmain control valve and said main burn-er, a secondary conduit extendingbetween said safetyqcontrol valve mechanism and said pilot burnerthroughwhich gaseous fuel is supplied to said pilot burner, said safetycontrol'valve mechanism being operative to control the supply'ffuelto-said main burner after said main control valve has-been opened,a solenoid by which said safety control valve mechanism is set inconditionto supply fuel to said pilot burner and said main burner, anelectromagnet'associated with saidsafety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a thermocouple; adapted to be heated l by saidpilot burnQ Z an electric. circuit between said thermocouple and saidelectromagnet through which said electromagnet is energized by saidthermocouple when :heated, a normally open switch in' said thermocouplecircuit, a solenoid-transformer having a primary winding and a'secondarywinding, -a;master.swi tch operative when closed to effectjenergizationof said solenoid-transformer, a-primary' circuit which includes saidprimary winding and saidmaster switch, a secondary circuit in which saidelectric ignition element said solenoid; and said secondary windingareudisposed' 116 in series with each othen'said. solenoid transformerbeing operative when energized to close said normallyopen switch and toenergize said electric ignitionel-ement and said solenoid, meansoperative to break said secondary circuit anddeenergizeasaid electricignition element andsaid solenoid after said pilot burner has beenignited by said electric ignition element, and clock actuated timecontrollmechamsm.operative to close and open said'master switch atpredetermined set times.

7. In an automatic ignition and control apparatus-of' thecharacter'described, the combina-' tion. of a main burner, a pilotburner operative to ignite said mainburner, an electric ignition elementoperative to ignite said pilot burner, a conduit through-which gaseousfuel is supplied to, saidmain burner, :a manually operable maincontrolvalve by whichthe supply .of' fuel 'tosaid main burner isprimarily controlled, a safety control valve mechanism interposed insaid conduit between said main control valve and said main burner, asecondary conduit extending between said safety control valve mechanismand said pilot burner through which gaseous'fuel' is suppliedto saidpilot burner, said safety control=valve mechanism being operative tocontrol the'supply of fuel to said main-burnerafter said maincontrolvalve has been opened; a solenoid by which said safety control valvemechanismis set in condition to supply-fuel to said pilotburner and saidmain burner, an electromagnet associated with said safety ,control valvemechanism and operative-when energized to maintain said safety control,valve mechanism insaid set condition, a thermocouple adapted tobeheated-by said pilot burner, an electric circuit between saidthermocouple and said electromagnet through which said electromagnet isenergized by said thermocouple when heated, a normally open switch insaid thermocouple circuit,.a' cam associated with said main controlvalveand operative to. close said normally opengswitch simultaneously withthe opening of said main control valve, a transformer having at primarywinding and a secondary 1 winding, a master switch operative when closedto effect energization of said transformer, a ,primary circuit whichincludes said primary winding and said master switch, a second circuitin which said electric ignition element said solenoid and said secondarywindingare disposed in series with each other, said transformer beingoperative when energized to energize,said-electric ignition element andsaidsolenoid, means operative to break said secondary circuit and deenergize said electric ignition element and said solenoid after; saidpilotburner has been ignited by said electric ignition; elements, andclock actuated time control mechanism operative to close and open saidmaster switch at predetermined set times. q

8..In an automatic ignition' and control apparatus of the characterdescribed, the combination of a main burner,-a pilotburner operative toignite said main burner, an electric ignition element operative'to'ignite said pilot burner, a conduit'through which gaseous fuel issupplied to said. main burner, a manually operable main control valve bywhich the supply of fuel to said main burneris primarily con,gas'eous'fuel is supplied to said pilot burner, said safety controlvalve mechanism being operative to control the supply of fuel to saidmain burner after said main control valve has been opened, a solenoid bywhich said safety control valve mechanism is set in condition to supplyfuel to said pilot burner and said main burner, an electromagnetassociated with said safety control valve mechanism and operative whenenergized to maintain said safety control valve mechanism in said setcondition, a thermocouple adapted to be heated by said pilot burner, anelectric circuit between said thermocouple and said electromagnetthrough which said electromagnet is energized by said thermocouple whenheated, a normally open switch in said thermocouple circuit, asolenoid-transformer having a primary winding and a secondary winding, amaster switch operative when closed to effect energization of saidsolenoid-transformer, a primary circuit which includes said primarylwinding and said master switch, a secondary circuit in which saidelectric ignition element said solenoid and said secondary winding aredisposed in series with each other, said solenoid-transformer beingoperative when energized to close said normally open switch and toenergize said electric ignition element and said solenoid, meansoperative to break said secondary circuit and de-energize said electricignition element and said solenoid after said pilot burner has beenignited by said electric ignition element, and clock actuated timecontrol mechanism operative to close and open said master switch atpredetermined set times, said means comprising a normally closed switchin said secondary circuit and a thermostatic element adapted to beheated by said pilot burner and operative when heated to open saidnormally closed switch.

9. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner is primarily controlled, asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel is supplied to said pilot burner,

said safety control valve mechanism being operative to control thesupply of fuel to said main burner after said main control valve hasbeen opened, a solenoid by which said safety .control valve mechanism isset in condition to supply fuel to said pilot burner and said mainburner, an electromagnet associated with said safety control valvemechanism and operative when energized to maintain said safety controlvalve mechanism in said set condition, a thermocouple adapted to beheated by said pilot burner, an electric circuit between saidthermocouple and said electromagnet through which said electromagnet isenergized by said thermocouple when heated, a normally open switch insaid thermocouple circuit, a cam associated with said main control valveand operative to close said normally open switch simultaneously with theopening of said main control valve, a transformer having a primarywinding and a secondary 'winding, a master switch operative when closeding and said master switch, a secondary' circuit injwhich said electricignition element saidsolenoid and said secondary winding are disposedinseries with each other, said transformer being operative whenenergized. to energize said electric ignition element and said solenoid,means operative to break said secondary circiut and de-energize saidelectric ignition element and said solenoid after said pilot burner hasbeen ignited by said electric ignition element, and clock actuated timecontrol mechanism operative to close and open said master switch, atpredetermined set times, said means comprising a normally closed switchin said secondary circuit and a thermostatic element adapted to beheated by said poilot burner and operative when heated to open saidnormally closed switch.

10. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner,'a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner is primarily controlled, asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel is supplied to said pilot burner, said safetycontrol valve mechanism being operative to con-trol the supplyvof fuelto said main burner after said main control valve has been opened, asolenoid by which said safety control valve mechanism is set incondition to supply fuel to said pilot burner and said main burner, anelectromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safely control valve mechanismin said set conditiona thermocouple adapted to be heated by said pilotburner, an electric circuit between said'thermoflcouple and saidelectromagnet through which said electromagnet is energized by saidthermocouple when heated, a normally open switch in'said thermocouplecircuit, means rendered operative by the closing of said main controlvalve to close said normally open switch, a transformerhaving-a primarywinding and a secondary winding, a master switch operative when closedto effectenergization of said transformer, a primary'circuit whichincludes said primary winding and said master switch, a secondarycircuit in which; said electric ignition element, said solenoid and saidsecondary winding are disposed in series with each other, saidtransformer being operative when energized to energize said electricignition element and said solenoid, and means operative to break saidsecondary circuit and 'de-energizje'said elec tric ignition element andsaid solenoid after said pilot burner has been ignited by said electricignition element. 11. In an automatic ignition and control apparatus ofthe character described, the combination of a main burner, a pilotburner operative to ignite said main burner, an electricignition elementoperative to ignite said pilot burner,'a conduit through which gaseousfuel is supplied to said main burner, a manually operable main con trolvalve bywhich the supply of fuel'tosaid main burneris primarilycontrolled, a safety control "tween 'said "main control valve and saidmain fbu'rn'er, a secondary conduit extending between said safetycontrol valve mechanism and said pilot burner through which gaseousfuelis supplied to said pilot burner, said safety control valvemechanism being operative to control the supply jof fuel to said-mainburner after said main control'valve has been opened, a solenoid bywhich said safety control valve mechanism is set in condition to supplyfuel to said pilot burner and said main burner, an electromagnetassociated said electromagnet is energized by said thermocouple whenheated, a normally open switch in said-thermocouple circuit; meansrendered operativ'e' by the closing of 'saidmain control valve to. closesaid normally open switch, a transformer ,having'a primary winding and asecondary windinc, 8/ master switch operative when closed toffectenergization of said transformer, a primary circuit 'which'includessaid primary winding and said master switch, a secondary circuit inwhich said electric ignition element, said solenoid and said secondarywinding are disposed in series with each -other,-said transformer beingoperative when energized to energize said electric ignition eleinentandsaid solenoid, means operative to break said secondary circuit andde-energize said electric-ignition element and said solenoid after saidpilot burner has been ignited by said electric ignition element,andclock actuated time control mechanism operative to close and open saidmas- -ter switch at predetermined set times.

12. In an automatic ignition and control apparatus of the characterdescribed,'the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner, a con- ,duit'threugh which gaseous fuel issupplied to said-main -burner, a manually operable main control valve bywhich'the supply of fuel to said mainburner is primarily controlled, 2.safety co ntrol'valve mechanism interposed in said conduit between saidmain control valve andlsaid main burner, a secondary conduit extendingbetween said safety control valve mechanism and ,said pilot burnerthrough which gaseous fuel is supplied to said pilot burner, saidsafetycontrol valve mechanism being operative to control. the

supply of fuel to said main burner after said main control valvehas beenopened, a solenoid .by which said safety control valve mechanism resetin condition to supply fuel to said pilot burner and said main burner,an electromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a thermocouple adapted to 'be heated by saidpilot burner, an electric circuit between said thermocouple and saidelectromagnet tli'ro'u'gh'which said electromagnet .is energized by said"thermocouple when heated, a normally open switch in said thermocouplecircuit, means rendered operative by the closing of said main controlvalve to close said normally open switch, a transformer having a'primarywinding and a secondary rwinding, a master switch operative whenclosed'to effect energization of said transformer, a primary circuitwhich includes said primary winding and said master switch, a secondarycircuit-in whichsaid electric ignition element-said solenoid and saidsecondary-winding are disposed inseries with each'other, saidtransformer being operative when energized to energize said electricignition element and said sole noid, means operative'to break saidsecondary circuit and ole-energize said electric ignition ele- 'ment andsaid solenoid after said pilot burner has been ignited by said electricignition element, and clock actuated time control mechanism operative toclose and open said master switch at predetermined set times, said meanscomprising a normally closed switch in said secondary circuit and athermostatic element adaptedto be heated by said pilot burner andoperative when heated to open said normally closed switch.

13. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electricignition element operative toignite" said pilot burner; a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fueltosaid main burner is primarily controlled, asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanismand said pilot burner throughwhichgaseous fuel is supplied to said pilot burner, said safety controlvalve mechanism being operative to control the supply of fuel to saidmain burner after said main control valve has been opened, a solenoid bywhich said safety control valvemechanismis set in condition to supplyfuel to said pilot burner and said main burneryanelectromagnetrassociated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a thermocouple adapted to be heated by said pilotburner, an electric circuit between said thermocouple and saidelectromagnet through which said electromagnet 'isenergized by saidthermocouple when heated, a normally open switch in said thermocouplecircuit, a solenoidtransformer having a primary winding and a secondarywinding, a master switch operative when closed to effect energization ofsaid solepilot burner has been ignited by said electric ignitionelement.

14. In an automatic ignition and control apparatus 'of the characterdescribed, the combination of a main burner, a pilot burner operative-to ignitesaid main burner, an electric ignition element operativeto'ignite said pilotburner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burneris primarily controlled, asafety control valve mechanism interposed in-said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel'is supplied to said pilot burner, said safetycontrol valve mechanism-being operative to control the supply of fuel tosaid main burner after said main control valve has been opened,a.solenoid by which said safety control valve mechanism is set incondition to supply fuel to. .said pilot burner and said main burner, anelectromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a thermocouple adapted to be heated by said pilotburner, an electric circuit between said thermocouple and saidelectromagnet through which said electromagnet is energized by saidthermocouple when heated, a normally open switch in said thermocouplecircuit, a cam associated with said main control valve and operative toclose said normally open switch simultaneously with the opening of saidmain control valve, a transformer having a primary winding and asecondary winding, a master switch operative when closed to effectenergization of said transformer, a primary circuit which includes saidprimary winding and said master switch, a secondary circuit whichincludes said secondary winding and said electric ignition element, saidtransformer being operative when energized to effect energization ofsaid solenoid and said electric ignition element, and means operative toeffect deenergization of said solenoid and said electric ignitionelement after said pilot burner has been ignited by said electricignition element,

15. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner is primarily controlled asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuelis supplied to said pilot burner, said safetycontrol valve mechanism being operative to control the supply of fueltosaid main burner after said main control valve has been opened, asolenoid by which said safety control valve mechanism is set incondition to supply fuel to said pilot burner and said main burner, anelectromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safety control ,valvemechanism in said set condition, a thermocouple adapted to be heated bysaid pilot burner, an electric circuit between said thermocouple andsaid electromagnet through which said electromagnet is energized by saidthermocouple when heated, a normally open switch in said thermocouplecircuit, means rendered operativeby the opening of said main controlvalve to close said normally open switch, a transformer having a primarywinding and a secondary winding, a master switch operative when closedto effect energization of said transformer, a primary circuit whichincludes said primary winding and said master switch, a secondarycircuit which includes said secondary winding and said electric ignitionele- ,ment, said transformer being operative when energized to effectenergization of said solenoid .22 operative to effect de-energization ofsaid solenoid and said electric igntion element after said pilot burnerhas been ignited by said electric ignition element. l 16. In anautomatic ignition and control apparatus of the character described, thecombination of a main burner, a pilot burner-soperative to ignite saidmain burner, an electric ignition element operative to ignite said pilotburner, a conduit through which gaseous fuel is supplied to said mainburner, a manually operable main control valve bywhich the supply offuel to said main burner is primarily. controlled, a safety controlvalve mechanism interposed in said con duit between said main controlvalve and said main burner, a secondary conduit extending between saidsafety control valve mechanism and said pilot burner through whichgaseous fuelis supplied to said pilot burner, said safety control valvemechanism being operative to-control-the supply of fuel to said mainburner after said main control valve has been opened, a solenoid bywhich said safety control valve mechanism is set in condition to supplyfuel to said pilot burner and said main burner, anelectromagnetassociated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a

thermocouple adapted to be heated by saidpilot having a primary windingand a secondary wind ing, a master switch operative when closed toeffect energization of said solenoid-transformer, a primary circuitwhich includes said primary winding and said master switch, a secondarycircuit which includes said secondary winding and said electric ignitionelement, said solenoidtransformer being operative when energized-toclose said normally open switch and to effect energization of saidelectric ignition element and said solenoid, means operative to effectde-energization of said electric ignition element and said solenoidafter said pilot burner has been ignited by said electric ignitionelement, andclock actuated time control mechanism operative to close andopen said master switch at predetermined set times.

17. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operativetoignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner is primarily controlled, asafety control valve mechanism interposed in said iconduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel is supplied to said pilot burner, said safetycontrol valve mechanism being operative to control the supply of fuel tosaid main burner after said main control valve has been opened, asolenoid by which said safety control valve mechanism is set incondition to supply fuel to said pilot burner and said main burner, anelectromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin -said set con i223 -dition,-i 25% thermocouple; adapted to beheatedty said :pilot burner; an, electriclcircuitlbetweenusaidvthermocouple and said ,-electromagnet through which said electromagnetis energized v:bymsaid thermocouple when heated, ..a normally openswitch" in said thermocouple. circuit, a cam associated =withv said maincontrol. valve;,andopera *tivedzo closesaidnormally:open switchsimultaneously with theopening of:said main control valve,aa transformerhaving a primary winding andansecondary winding, a masterswitchoperative when closed-.130. effectenergization' ofsaidtransformena primary circuitpwhich includes said :primary: winding and:said 1 master :switch, -a. -sec.ondarycircuit which includes saidsecondary swindingzand, said electric ignition element, said transformerbeing. operative:v whenwenergized to effect energizationof said solenoidand said elec- ;triciignitionelement, means-operative to: effect-1de-energization of said solenoidandsaid'electric ignition element.after .said pilot burnerhas been .:ignited-by said:electricignition1elernent,"and clock actuated wtime control mechanismoperative to close::and.- open said Inaster switch :atpredeteriwminedset times.

* 18.:'In :an automatic ignition and cntrol ;apparatuszof thecharacterdescribed, the'combina- .tion of; a mainburner, a; pilot burneroperative :to.'.ignite said main burner,san electric ignition "elementoperativeto ignite. saidpilot'burner; a conduitthrough whichgaseous fuelis suppliedto --saidanain'burner, a manually operable main con-:trol-Ivalve by which the. supplyof fuel to said main .burner isprimarily. controlled, asafety. control -valve mechanism interposed insaid conduit between said main control valve'and said main burner, asecondary conduit extending between said safety-control valve-mechanismandsaid pilotburner through which gaseousfuel is sup- :plied tosaidpilotburnen said safety control "valve mechanism being'operative to controlthe supply-. of-fuel to said main burner after-said -main control valvehas been opened, a solenoid by which-said-safety control valvemechanismis setin condition to supply fuel tosaid pilot burner 'ar'id-said mainburner an electromagnet associated with said safety control valvemechanism and operative when energized to maintain-said safety controlvalve mechanism insaid'set condition, -a thermocouple adapted to beheated by said pilot burner, an electric circuit between saidthermocouple and said electromagnet through which'said electromagnet isenergized by said thermocouple when heated, a normally open switch insaid thermocouple circuit, means ren- -dered*operative--by the-closingofsaid main con- -trol valve to close said normally open switch, atransformer having a primary'winding and a -sec0ndary winding, a masterswitch operative when closed to-efiect energization of 'said transjformen a primary circuit which includes said --pr imary winding and saidmaster switch, a secondary circuit --which includes said secondarywinding and said; electric ignition 'element,- said transformer beingoperativewhen energized to efiectenergization of said solenoid and saidelectricjignition element means operative to effect i'de-energization ofsaid solenoid and said electric ignition element: after said pilotburner has been ignited by "said electric ignition element, andclockactuated time control mechanism operative to closeandopensaidmaster switch at prede- -termined' set times. a V e 1 9.} In 1 anautomatic ignition and control apparatus Of the charactendescribed, thecombination of;a;main:.burner,;.a piIQtburneroDerati'VQt6 .ignite saidmainiburner, .an electric ignition-rele- ;.ment=-.operative:.to.:ignitesaidlpi'lot burnerhaicon- :duit through;whichgaseous? fuel is supplied;to said. :main burner, a .Ymanually; operable .rmain 'control'valvebylwhichthe supplylofifuel .to said- .mainburnerisprimarily controlled,a safety con trolivalve mechanismlinterposed in said conduit she-tweensaid-main-control valve .and said main --bur-ner, a secondary. conduitextending between :saidisafety c0n-trol'-.=va1ye mechanism/rand saidpilot iburner: through which gaseous fuel is supplied to' said pilotburnensaid safety control valve mechanism being operative to control-thesupply 0f fuel to said wmain burneratter: said =main control valve hasbeen opened, a solenoid by which said: safety control valve mechanism is-set in condition :to supply fuel tosaid pilot burn- L or and said mainburner, an electromag-net -associatedwithsaidsafety control valvemechanism andoperative-when energized to maintain said safety-controlvalve mechanism-insaid set condition, a thermocoupleadapted to be heatedby said pilot burner, anelectric circuit between said thermocouple andsaid' electromagnet through which-'- said electromagnet is energized--by-- said thermocouple ---when heated, a normally open switch in' saidthermocouple-circuit, a solenoidtransformer having a --primary windingand a secondary winding, a master switch operative when "closedto-effect energization of said solenoid-transformer, a primary circuitwhich includes said 1, primary -w-inding and said -master switch, a'secondary circuit which includes-said secondary 'windingandsaidjelectric ignition element, said solenoid transformer beingoperative when energized to close said normally openswitch :and toeffect energization of said electric ignition element-and said'solenoid,means-operative to efiect de-energization:of said electric ignitionelement and, said solenoid: after said 'pilot' burner has beenignited-by said electric ignition element, and clock actuated timecontrol mechanism operative to. closeand'open said master switchiatpredetermined set times; said means comprising a normally closed switchin'said secondary cirsuit and a thermostatic. element adaptedtobe heatedby said pilotburner and operative'when heated to open said normallyclosed switch. 7

I20.'In an automatic ignition and control apparatusofthe characterdescribed, the combination of a main burner, apilot burner operativetojgnite said main burner an electric ignition elementoperativetdignitesaid pilot burner, a conduit'jthrough which, gaseous fuel isv suppliedto saidimain burner, a manually operable main controlvalve by which thesupply .offuel' to said mainburner isprimarily controlled, asafetycontrol valve mechanism, interposed in said conduit between said, mainvcontr'ol valve, and, said main burner, a secondary, conduit eXtending sbetween said, safety vcontrol valve mechanismandjsaid pilot burnerthrough whichgaseousiuel is supplied i-to sa id pilot burner, saidsafety control valve mechanism being operative to control the supply-offuel to said main'burnerafter said main control valvehas been opened; asolenoid by which said-safety control valve mechanism is set inconditionto supplyfuel to said pilot burner and saidmain burner,"an-electrornagnetassoci- -atedwith-said safety 'control valve mechanismand-operativewhen energized to maintain said safetycontrol valvemechanism in said set condition,' a thermocouple adaptedto be heatedbysaid pilot burner an electric circuitbetween said thermocouple and saidelectromagnet through which said electromagnet i energized by saidthermocouple when heated, a normally open switch in said thermocouplecircuit, a cam associated with said main control valve and operative toclose said normally open switch simultaneously with the opening of saidmain control valve, a transformer having a primary winding and asecondary winding, a master switch operative when closed to efiectenergization of said transformer, a primary circuit which includes saidprimary winding and said master switch, a secondary circuit whichincludes said secondary winding and said electric ignition element, saidtransformer being operative when energized to effect energization ofsaid solenoid and said electric ignition element, means operative toeffect de-energization of said solenoid and said electric ignitionelement after said pilot burner has been ignited by said electricignition element, and clock actuated time control mechanism operative toclose an open said master switch at predetermined set times, said meanscomprising a normally closed switch in said secondary circuit and athermostatic element adapted to be heated by said pilot burner andoperative when heated to open said normally closed switch.

21. In an automatic ignition and control apparatus of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said main burner is primarily controlled, asafety control valve mechanism interposed in said conduit between saidmain control valve and said main burner, a secondary conduit extendingbetween said safety control valve mechanism and said pilot burnerthrough which gaseous fuel is supplied to said pilot burner, said safetycontrol valve mechanism being operative to control the supply of fuel tosaid main burner after said main control valve has been opened, asolenoid by which said safety control valve mechanism is set incondition to supply fuel to said pilot burner and said main burner, anelectromagnet associated with said safety control valve mechanism andoperative when energized to maintain said safety control valve mechanismin said set condition, a thermocouple adapted to be heated by said pilotburner, an electric circuit between said thermocouple and saidelectromagnet through which said electromagnet is energized by saidthermocouple when heated, a normally open switch in said thermocouplecircuit, means rendered operative by the closing of said maincontrolvalve to close said normally open switch, a

transformer having a primary winding and asecondary winding, a masterswitch operative when closed toeffect energization of said transformer,a primary circuit which includes said primary winding and said masterswitch, a secondary circuit which includes said secondary winding andsaid electric ignition element, said transformer being operative whenenergizedto effect energization of said solenoid and said electricignition element, means operative to efiect de-energization of saidsolenoid and said electric ignition element after said pilot burner hasbeen ignited by said electric ignition element, and clock actuated timecontrol mechanism operative to close and open said master switch atpredetermined set times, said mean comprising a normally closed switchin said secondary circuit andv a thermostatic element adapted to beheated by said pilot burner and operative when heated'to opensaidnormally close-d switch.

22.'In an automatic ignition and control apparatus-of the characterdescribed, the combination of a main burner, a pilot burner operative toignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied to said main burner, a manually operable main control valve bywhich the supply of fuel to said when closed to effect energization ofsaid solenoid, a relay operative when energized to close said solenoidswitch, an electromagnetas sociated with said safety control valvemechanism and operative when energized to maintain said safety controlvalve mechanism in-said set condition, a-thermocouple adapted to beheated, by said pilot burner, an electric circuit between saidthermocouple and said electromagnet through which said electromagnet isenergized by said thermocouple when heated, a normally I open switch insaid thermocouple circuit, means rendered operative by the closing ofsaidmain control valve to. close said normally open switch, atransformer having a primary winding and a secondary winding, a master"switch operative when closed to effect energization of said transejformer, a. primary circuit which includes said primary winding and saidmaster switch, a sec: ondary circuit in which said electric ignitionele-.

ment said relay and said secondary winding are" disposed in series witheach other, said transformer being'operative when energized to energizesaid electric ignition element and said relay, and means operative tode-energize said electric ignition element and said relay after saidpilot burner has been ignited by said electric ignitionelement. ,l

23. In an automatic ignition and control ap paratus of the characterdescribed, the combination of a mainburner, a pilot burner oper-' ativeto ignite said main burner, an electric ignition element operative toignite said pilot burner, a conduit through which gaseous fuel issupplied tosaid main burner, amanually operablemain control valve bywhich the supply of fuel to said main burner is primarily 'controlled,.asafety con trol valve mechanism interposed in' said conduit.

between said main control valve and saidmain burner, a secondary conduitextendingbetween said safety control valve mechanism and saidpilotburner through which gaseous fuel is supplied to said pilot burner,vsaid safety control valve mechanism being operative to control the.supply of fuel to said main burner after said main:

control valve has been opened, a solenoid by which said safety controlvalve mechanism is set in condition to supply fuel to said pilot burnerand said main burner, a solenoid switch operative when closed to effectenergization of said solenoi'd, a, relay-.operative when energized-toclose saidsolenoid" switch; anelectromagnet associated with said" safetycontrol vaive mechanism and operative When' energizedtomaintain saidsafety control valve mechanism in saidset condition; a 5 thermocoupleadapted to lie-heated "by said pil'otburner; an electric'circuitbet-ween said thermo couple and said electTomagnet through which"saidi'electromagnet is energized'by said thermo couple-when '-h'eated;"a-"normally open switch in" 1 o: saidthermocouplecircuit, means renderedoper-- ative icy-the closing ofsaid main control valve toclo'sesaidnormallyopenswitch} a=transformer having-a primary windingancl'a'secondar rwind ingfa master'-*switc'h operative when closed-*td 1eii'efct energization of said tran'sformery' aprimary-"j circuit whichincludes said primary winding and-said master switch; ase'cOnda'ry cir--cuit" in which said "electric ignition element saidrelay and saidsecondary windingare disposed in series with each other, saidtransformer being op'erative when energized- *to' energize said elem"trio ignitionelement andsaid relay; and' means' operative-tode-energize-sai'd electric'igniti'on ele-" mentand saidrelay*-after'-said-'pilot-burner has been ignited b'yfsaidelectricignition element,- and clock actuated time control mechanism oper-"--ati'veto 'close andfopensaid 'masterswitchat predetermined set times;

24;"Ir'r'an 'aotom'atic'-'ignition and controlappa- J ratfisof thecharacter described;- the combination of a main burner; a pilot burneroperative to ignite said main burner; an electric ignition 'elen'ient-op-erative to ignite said pilotburnen'aconduiflth'roughw'h'i'cligaseous fuel is't pli'edto' saidimain.burnerjamanuallvoperablemaincon trolvalve' 'by which the supply, of fuel to s aid niairi burneris primarily controlled, a'safety controlvalvamechanism"'interposedfinsaid conduiir'between said "main" controlvalve and" saidfimain burner; at secondary conduit extending betweensaid? safety control? valve mechanism and said pilot b'urn'enthrough'whichtgaseousrfuel is sup-' plied ,to said" pilot burner, said' safe'tycontrol:- valvefmechanismibeing"operative "to 'control'itha supply 'of.fuel to said main" burner after said main control :valve hasfbeenopened, 'a solenoid! by which said safety? control valve "mechanism" issetin .condition to supply fuel to' said'pilot' bur ner-andlsaid mainburner, a' solenoid switch"; 503 operative when" closed to; effectenergiz'ationof"; said solenoid,'a relay operative when energizeditoclose said solenoid switch, .an electromagnetl'as sociated with-saidsaftycontr'olvalve mechanism and operative when energized tolmaintainsaid 5,5; safety control valve mechanism in said'set 'cona dition,'aithermocouple adapted to be heated by.- said-pilot zb'urner, anelectric cirbuitbiettzeen said; tliermocouple and; saidelectroma'gntvthrough. which saidelectromagnet isenergizedfibyasaid 9 thermocoupleWhenheated, a normally, open switch" in'saidth'ermocouple circuit; meansren-I dered'operative b the 'openi'ngof 'saidimain con trol' 'valve"to"c1ose "said normally"open switch; a transformerhavina aprimarywinding and a- 05. secondary Winding, a master"switch operativewhen closed co-effect energiz'ation of said transformer; aprimarycircuit Wh'ichJ includes said-i primary windiiig andsaidmastr switch} asec on'dary circuit in which'saidelectricignition ele 7 ment-said="relay "and" said secondary wiridingare disposed in series \m'theach is other; said transformer "being=operative-=when energized to energize sa-id electric ignition element and said relay, and' meansoperative-to de-en'ergizesaid electric ignition =elem'ent'and saidrelayafter said pilot burner has loeen -igr-iitd"by said-electric ignitionelement, said means comprisinga norm'allyclosed switch 'in saidsecondary circuitand a thermostatic element adapted tobe=heated by saidpilot 1 burner and ope'rative when'h'eated to open :said normally closedswitehs 25. Iii-an automaticignition and control appa 1 rains of 'thecharaeter described-, the combina tio'n of a main burner; a pilotz'burner operative to ignite sai'd main burner; anelectric -ignitionelementoperative to"-ignite saidpilot burner, a conduitthrougnwhichgaseous fuel is supplied to said main; burner; amanually operable-=maini control valve by -vvh-ich the sup-ply 0f iuel to 'said mainburne1'- ispri'r'naid-133 controlled; a safetycontrol valve mechanisln' interposedin 'said con' duit" between said main control valveand said main burner;a --secondary conduit extending between" said saf ty controlvalvemechanism and said-pilot bui'ner through "which gaseous fuel issupplied to said pilot burnergsaid safety control valve mechanism beingoperative to control the supply o-f-- fuelto s-aid mai-n burner aftersaid main control val-ve has ibeen -opened; a sole'noid" by which saidsafety control valve =mechan'ism'is set ir'rcondition to isuppl'y'itielto saiolpildt burner and-said main'burnew a solenoid switch opera ti'vewhen closed-' to eifct energization of said solenoid a relay'==operative when energized to clo'se' said solenoid switchy anelectromagnet 'as sociated with saidsafety-control valve mechanismand-operative when 'energizedto maintain said safety control valvemechanism insaid 'set condition, a thermocouple adapted to he heated bysaid pilot "burn'er ani electric circuit between said thermocouple andsaid elctfomagnet through which" said electromagnet -is= energized bysaid thermocouple -when heated? a normally open" switch in saidthermocouple I circuit, l means rendred operative b'y the opening ofsaid5 main control valve to' close -said normally open switch,- atr-ansforme'r having a primary winding anda secondarywinding, a masterswitch operative when closed t'o effe'ct energizati'on ofsaidtransformer, a primary cir'cuit -which"- includes said primaryWinding 'and' said master switch, a secondary' circ'uit in'wh-ich saidelectricignition; ele-' ment said relay-and sai'd secondary-Windingaredisposed in series-*with -each other,said*trans-- former beingoperative-When energized to energize-said "electric ignition element andsaid relay, means operative to tie-energize "said electric ignitionelement and said'relay after said pilot burnerhas been ignitedby'said'electric-ignition element, and block-actuated timecontrolmechanism oper-- ativeto close-a11d open -said'-master switch atpredetermined set times; said means comprising anormally closed Switchin said secondary circuil and: 'athermostatic element adapted to beheate by 'saidpilot burner and operative' when heate to operrsaid-vnorm'ally closed switch.

CHARLES-E'M--MAYERI No references .cited. i

